Fix deprecated usage of torch.nn.utils.weight_norm

[SaeedForoutan]

42ef14a: The previous implementation in darts.darts.models.forecasting.tcn_mode was using torch.nn.utils.weight_norm, which is deprecated in favor of torch.nn.utils.parametrizations.weight_norm. This commit replaces two occurrences of torch.nn.utils.weight_norm with the recommended torch.nn.utils.parametrizations.weight_norm to resolve the deprecation warning.

8cc12c8: The .pt string is yet existed in the checkpoint file .ckpt. I filtered it out.

Change Made:

• Replaced torch.nn.utils.weight_norm with torch.nn.utils.parametrizations.weight_norm, and filtering out the .pt string.

Testing:

• Tested the changes by using the TCN (Temporal Convolutional Network) model in darts.
• Confirmed that the deprecation warning related to the usage of torch.nn.utils.weight_norm no longer appears when utilizing the TCN model.
• Ran existing test suites to ensure that the functionality of the package is not affected by the changes.
• Tested backward compatibility to verify that existing codebases relying on the TCN model continue to function as expected after the update.